lbessard@70: /*
lbessard@70:  * (c) 2003 Mario de Sousa
lbessard@70:  *
lbessard@70:  * Offered to the public under the terms of the GNU General Public License
lbessard@70:  * as published by the Free Software Foundation; either version 2 of the
lbessard@70:  * License, or (at your option) any later version.
lbessard@70:  *
lbessard@70:  * This program is distributed in the hope that it will be useful, but
lbessard@70:  * WITHOUT ANY WARRANTY; without even the implied warranty of
lbessard@70:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
lbessard@70:  * Public License for more details.
lbessard@70:  *
lbessard@70:  * This code is made available on the understanding that it will not be
lbessard@70:  * used in safety-critical situations without a full and competent review.
lbessard@70:  */
lbessard@70: 
lbessard@70: /*
lbessard@70:  * An IEC 61131-3 IL and ST compiler.
lbessard@70:  *
lbessard@70:  * Based on the
lbessard@70:  * FINAL DRAFT - IEC 61131-3, 2nd Ed. (2001-12-10)
lbessard@70:  *
lbessard@70:  */
lbessard@70: 
lbessard@70: 
lbessard@70: 
lbessard@70: /* Determine the data type of a variable.
lbessard@70:  * The variable may be a simple variable, a function block instance, a
lbessard@70:  * struture element within a data structured type (a struct or a fb), or
lbessard@70:  * an array element.
lbessard@70:  * A mixture of array element of a structure element of a structure element
lbessard@70:  * of a .... is also suported!
lbessard@70:  *
lbessard@70:  * A reference to the relevant base type __definition__ is returned.
lbessard@70:  * This means that if we find that the variable is of type MY_INT,
lbessard@70:  * which was previously declared to be
lbessard@70:  * TYPE MY_INT: INT := 9;
lbessard@70:  * this class wil return INT, and __not__ MY_INT !!
lbessard@70:  *
lbessard@70:  *
lbessard@70:  *  example:
lbessard@70:  *    window.points[1].coordinate.x
lbessard@70:  *    window.points[1].colour
lbessard@70:  *    etc... ARE ALLOWED!
lbessard@70:  *
lbessard@70:  * This class must be passed the scope within which the
lbessard@70:  * variable was declared, and the variable name...
lbessard@70:  */
lbessard@70: class search_varfb_instance_type_c: public search_base_type_c {
lbessard@70:   private:
lbessard@70:     search_var_instance_decl_c search_var_instance_decl;
lbessard@70:     decompose_var_instance_name_c *decompose_var_instance_name;
lbessard@70:     symbol_c *current_structelement_name;
lbessard@70: 
lbessard@70:   public:
lbessard@70:     search_varfb_instance_type_c(symbol_c *search_scope): search_var_instance_decl(search_scope) {
lbessard@70:       this->decompose_var_instance_name = NULL;
lbessard@70:       this->current_structelement_name = NULL;
lbessard@70:     }
lbessard@70: 
lbessard@70: 
lbessard@70:     symbol_c *get_type(symbol_c *variable_name) {
lbessard@70:       this->current_structelement_name = NULL;
lbessard@70:       this->decompose_var_instance_name = new decompose_var_instance_name_c(variable_name);
lbessard@70:       if (NULL == decompose_var_instance_name) ERROR;
lbessard@70: 
lbessard@70:       /* find the part of the variable name that will appear in the
lbessard@70:        * variable declaration, for e.g., in window.point.x, this would be
lbessard@70:        * window!
lbessard@70:        */
lbessard@70:       symbol_c *var_name_part = decompose_var_instance_name->next_part();
lbessard@70:       if (NULL == var_name_part) ERROR;
lbessard@70: 
lbessard@70:       /* Now we try to find the variable instance declaration, to determine its type... */
lbessard@70:       symbol_c *var_decl = search_var_instance_decl.get_decl(var_name_part);
lbessard@70:       if (NULL == var_decl) {
lbessard@70:         /* variable instance declaration not found! */
lbessard@70:  	      return NULL;
lbessard@70:       }
lbessard@70: 
lbessard@70:       /* if it is a struct or function block, we must search the type
lbessard@70:        * of the struct or function block member.
lbessard@70:        * This is done by this class visiting the var_decl.
lbessard@70:        * This class, while visiting, will recursively call
lbessard@70:        * decompose_var_instance_name->get_next() when and if required...
lbessard@70:        */
lbessard@70:       symbol_c *res = (symbol_c *)var_decl->accept(*this);
lbessard@70:       if (NULL == res) ERROR;
lbessard@70: 
lbessard@70:       /* make sure that we have decomposed all strcuture elements of the variable name */
lbessard@70:       symbol_c *var_name = decompose_var_instance_name->next_part();
lbessard@70:       if (NULL != var_name) ERROR;
lbessard@70: 
lbessard@70:       return res;
lbessard@70:     }
lbessard@70: 
lbessard@70:     unsigned int get_vartype(symbol_c *variable_name) {
lbessard@70:       this->current_structelement_name = NULL;
lbessard@70:       this->decompose_var_instance_name = new decompose_var_instance_name_c(variable_name);
lbessard@70:       if (NULL == decompose_var_instance_name) ERROR;
lbessard@70: 
lbessard@70:       /* find the part of the variable name that will appear in the
lbessard@70:        * variable declaration, for e.g., in window.point.x, this would be
lbessard@70:        * window!
lbessard@70:        */
lbessard@70:       symbol_c *var_name_part = decompose_var_instance_name->next_part();
lbessard@70:       if (NULL == var_name_part) ERROR;
lbessard@70: 
lbessard@70:       /* Now we try to find the variable instance declaration, to determine its type... */
lbessard@70:       symbol_c *var_decl = search_var_instance_decl.get_decl(var_name_part);
lbessard@70:       if (NULL == var_decl) {
lbessard@70:         /* variable instance declaration not found! */
lbessard@70:         return 0;
lbessard@70:       }
lbessard@70: 
lbessard@70:       /* if it is a struct or function block, we must search the type
lbessard@70:        * of the struct or function block member.
lbessard@70:        * This is done by this class visiting the var_decl.
lbessard@70:        * This class, while visiting, will recursively call
lbessard@70:        * decompose_var_instance_name->get_next() when and if required...
lbessard@70:        */
lbessard@70:       unsigned int res = search_var_instance_decl.get_vartype();
lbessard@70:       
lbessard@70:       /* make sure that we have decomposed all strcuture elements of the variable name */
lbessard@70:       symbol_c *var_name = decompose_var_instance_name->next_part();
lbessard@70:       if (NULL != var_name) ERROR;
lbessard@70: 
lbessard@70:       return res;
lbessard@70:     }
lbessard@70: 
lbessard@70:   private:
lbessard@70:     /* a helper function... */
lbessard@70:     void *visit_list(list_c *list)	{
lbessard@70:       if (NULL == current_structelement_name) ERROR;
lbessard@70: 
lbessard@70:       for(int i = 0; i < list->n; i++) {
lbessard@70:         void *res = list->elements[i]->accept(*this);
lbessard@70:         if (res != NULL)
lbessard@70:           return res;
lbessard@70:       }
lbessard@70:       /* not found! */
lbessard@70:       return NULL;
lbessard@70:     }
lbessard@70: 
lbessard@70:     /* a helper function... */
lbessard@70:     void *base_type(symbol_c *symbol)	{
lbessard@70:         search_base_type_c search_base_type;
lbessard@70: 	return symbol->accept(search_base_type);
lbessard@70:     }
lbessard@70: 
lbessard@70: 
lbessard@70:   private:
lbessard@70:     /* We override the base class' visitor to identifier_c.
lbessard@70:      * This is so because the base class does not consider a function block
lbessard@70:      * to be a type, unlike this class that allows a variable instance
lbessard@70:      * of a function block type...
lbessard@70:      */
lbessard@70:     void *visit(identifier_c *type_name) {
lbessard@70:       /* look up the type declaration... */
lbessard@70:       symbol_c *fb_decl = function_block_type_symtable.find_value(type_name);
lbessard@70:       if (fb_decl != function_block_type_symtable.end_value())
lbessard@70:         /* Type declaration found!! */
lbessard@70: 	return fb_decl->accept(*this);
lbessard@70: 
lbessard@70:       /* No. It is not a function block, so we let
lbessard@70:        * the base class take care of it...
lbessard@70:        */
lbessard@70:       return search_base_type_c::visit(type_name);
lbessard@70:     }
lbessard@70: 
lbessard@70: /********************************/
lbessard@70: /* B 1.3.3 - Derived data types */
lbessard@70: /********************************/
lbessard@70: /*  structure_type_name ':' structure_specification */
lbessard@70:     void *visit(structure_type_declaration_c *symbol) {
lbessard@70:       return symbol->structure_specification->accept(*this);
lbessard@70:       /* NOTE: structure_specification will point to either a
lbessard@70:        *       initialized_structure_c
lbessard@70:        *       OR A
lbessard@70:        *       structure_element_declaration_list_c
lbessard@70:        */
lbessard@70:     }
lbessard@70: 
lbessard@70: /* structure_type_name ASSIGN structure_initialization */
lbessard@70: /* structure_initialization may be NULL ! */
lbessard@70: // SYM_REF2(initialized_structure_c, structure_type_name, structure_initialization)
lbessard@70:     void *visit(initialized_structure_c *symbol)	{
lbessard@70:       /* make sure that we have decomposed all strcuture elements of the variable name */
lbessard@70:       symbol_c *var_name = decompose_var_instance_name->next_part();
lbessard@70:       if (NULL == var_name) {
lbessard@70:         /* this is it... !
lbessard@70: 	  * No need to look any further...
lbessard@70: 	 */
lbessard@70: 	/* NOTE: we could simply do a
lbessard@70: 	 *   return (void *)symbol;
lbessard@70: 	 *       nevertheless, note that this search_varfb_instance_type_c
lbessard@70: 	 *       class inherits from the search_base_type_c class,
lbessard@70: 	 *       which means that it will usually return the base type,
lbessard@70: 	 *       and not the derived type (*). If we are to be consistent,
lbessard@70: 	 *       we should guarantee that we always return the base type.
lbessard@70: 	 *       To do this we could use
lbessard@70: 	 *   return (void *)symbol->accept(*this);
lbessard@70: 	 *       since this class inherits from the search_base_type_c.
lbessard@70: 	 *       However, in this case we don't want it to follow
lbessard@70: 	 *       the structs as this search_varfb_instance_type_c does.
lbessard@70: 	 *       We therefore have to create a new search_base_type_c
lbessard@70: 	 *       instance to search through this type without going
lbessard@70: 	 *       through the structs...
lbessard@70: 	 */
lbessard@70:         return base_type(symbol->structure_type_name);
lbessard@70:       }
lbessard@70: 
lbessard@70:       /* now search the structure declaration */
lbessard@70:       current_structelement_name = var_name;
lbessard@70:       /* recursively find out the data type of var_name... */
lbessard@70:       return symbol->structure_type_name->accept(*this);
lbessard@70:     }
lbessard@70: 
lbessard@70: /* helper symbol for structure_declaration */
lbessard@70: /* structure_declaration:  STRUCT structure_element_declaration_list END_STRUCT */
lbessard@70: /* structure_element_declaration_list structure_element_declaration ';' */
lbessard@70:     void *visit(structure_element_declaration_list_c *symbol)	{return visit_list(symbol);}
lbessard@70: 
lbessard@70: /*  structure_element_name ':' spec_init */
lbessard@70:     void *visit(structure_element_declaration_c *symbol) {
lbessard@70:       if (NULL == current_structelement_name) ERROR;
lbessard@70: 
lbessard@70:       if (compare_identifiers(symbol->structure_element_name, current_structelement_name) == 0)
lbessard@70:         return symbol->spec_init->accept(*this);
lbessard@70: 
lbessard@70:       return NULL;
lbessard@70:     }
lbessard@70: 
lbessard@70: /* helper symbol for structure_initialization */
lbessard@70: /* structure_initialization: '(' structure_element_initialization_list ')' */
lbessard@70: /* structure_element_initialization_list ',' structure_element_initialization */
lbessard@70:     void *visit(structure_element_initialization_list_c *symbol) {ERROR; return NULL;} /* should never get called... */
lbessard@70: /*  structure_element_name ASSIGN value */
lbessard@70:     void *visit(structure_element_initialization_c *symbol) {ERROR; return NULL;} /* should never get called... */
lbessard@70: 
lbessard@70: 
lbessard@70: 
lbessard@70: /**************************************/
lbessard@70: /* B.1.5 - Program organization units */
lbessard@70: /**************************************/
lbessard@70: /*****************************/
lbessard@70: /* B 1.5.2 - Function Blocks */
lbessard@70: /*****************************/
lbessard@70: /*  FUNCTION_BLOCK derived_function_block_name io_OR_other_var_declarations function_block_body END_FUNCTION_BLOCK */
lbessard@70: // SYM_REF4(function_block_declaration_c, fblock_name, var_declarations, fblock_body, unused)
lbessard@70:     void *visit(function_block_declaration_c *symbol) {
lbessard@70:       /* make sure that we have decomposed all strcuture elements of the variable name */
lbessard@70: 
lbessard@70:       symbol_c *var_name = decompose_var_instance_name->next_part();
lbessard@70:       if (NULL == var_name) {
lbessard@70:         /* this is it... !
lbessard@70: 	 * No need to look any further...
lbessard@70: 	 * Note also that, unlike for the struct types, a function block may
lbessard@70: 	 * not be defined based on another (i.e. no inheritance is allowed),
lbessard@70: 	 * so this function block is already the most base type.
lbessard@70: 	 * We simply return it.
lbessard@70: 	 */
lbessard@70: 	return (void *)symbol;
lbessard@70:       }
lbessard@70: 
lbessard@70:       /* now search the function block declaration for the variable... */
lbessard@70:       search_var_instance_decl_c search_decl(symbol);
lbessard@70:       symbol_c *var_decl = search_decl.get_decl(var_name);
lbessard@70:       if (NULL == var_decl) {
lbessard@70:         /* variable instance declaration not found! */
lbessard@70:  	return NULL;
lbessard@70:       }
lbessard@70: 
lbessard@70:       /* We have found the declaration.
lbessard@70:        * Should we look any further?
lbessard@70:        */
lbessard@70:       var_name = decompose_var_instance_name->next_part();
lbessard@70:       if (NULL == var_name) {
lbessard@70:         /* this is it... ! */
lbessard@70: 	return base_type(var_decl);
lbessard@70:       }
lbessard@70: 
lbessard@70:       current_structelement_name = var_name;
lbessard@70:       /* recursively find out the data type of var_name... */
lbessard@70:       return symbol->var_declarations->accept(*this);
lbessard@70:     }
lbessard@70: 
lbessard@70: };
lbessard@70: 
lbessard@70: 
lbessard@70: 
lbessard@70: 
lbessard@70: